$\dfrac{7}{10} - \dfrac{5}{10} = {?}$
Solution: $ = {\dfrac{7 \times 1}{10 \times 1}} - {\dfrac{5 \times 1}{10 \times 1}} $ $ = {\dfrac{7}{10}} - {\dfrac{5}{10}} $ $ = \dfrac{{7} - {5}}{10} $ $ = \dfrac{2}{10}$